Lubricating oil composition



Patented Mar. 30, 1948 LUBRICATING OIL COMPOSITION Edward S. Blake, Nitro, W. Va., assignor to Monsanto Chemical Company, St. Louis, Mo., a corporation of Delaware No Drawing. Application June 17, 1944, Serial No. 540,891

This invention relates to lubricating compositions and to methods of preparing the same and more particularly to lubricating compositions adapted for use under extreme pressure conditions.

Various types of modern machinery such as the hypoid gears in motor vehicles develop enormous pressures between engaged surfaces. The ordinary type of hydrocarbon lubricant composed only of a petroleum fraction is incapable of satisfying the severe requirements demanded in the proper lubrication of hypoid gears, bearing surfaces, metal cutting tools and the like, subjected to unusually heavy loads per unit area of surface. This fact has led to the development of the so-called extreme pressure lubricant which is composed of a suitable carrying agent, such as mineral oil, and another ingredient which imparts to the lubricating composition the property of maintaining between the engaged surfaces a lubricating film under the high pressures encountered.

Among the various E. P. bases which have been prepared and which have met with varying degrees of success are organic materials which contain sulfur or both sulfur and chlorine. The

present invention relates to the general type of organic materials which contain both sulfur and chlorine. The presence of chlorine frequently increases the effectiveness of organic sulfur compounds but this increased effectiveness is accompanied by increased corrosiveness and decreased stability. However, the new adjuvants while considerably more effective than the corresponding chlorine free sulfur compounds actually appear to be more stable and are not corrosive.

A primary object of this invention is to provide a new and novel sulfur-and-chlorine-containing material capable of imparting extreme pressure lubricant properties to a lubricating oil composition otherwise incapable of withstanding extreme pressure conditions. A further object is to provide a mineral oil adjuvant which is not corrosive and yet is a very effective extreme pressure addition agent. Still further objects are to provide extreme pressure addition agents which are cheap and easily prepared.

In accordance with this invention it has been discovered that chloraralkyl esters of thio acids are very effective extreme pressure lubricant agents. The addition to hydrocarbon or fatty lubricating oils of small amounts of chloraralkyl esters of thio acids provides lubricating compositions which not only satisfy all of the primary requirements of extreme pressure lubricants but,

17 Claims. (Cl. 252-484) in addition do not tend to form gum, foul or corrode metal surfaces nor. separate into their constituent parts in long continued use. Examples of suitable thio acids from which the new E. P. agents may be derived include carbothiolic acids (RCO.SH), carbothionic acids carbodithioic acids (R-CSSH), mono-, diand trithiocarbonic acids where Y is oxygen or sulfur, at least one Y being sulfur, and thiocarbamic acids In general derivatives of thiocarbonic acids are preferred, that is to say products of the structure where R is a chloraralkyl radicle,'Y is sulfur or oxygen at least one of them being sulfur and R represents alkyl, aryl, aralkyl or alkyaryl.

The amounts of chloraralkyl esters required to be added to hydrocarbon or fatty lubricating oils for the preparation of compositions of this invention vary somewhat, depending upon the character of the lubricating stock used as a base, and the severity of the service for which they are designed; however, the active agent is always present in minor amounts with respect to the oil base and in general varies between about 1% and about 10% of the oil base by weight although amounts outside of this range can be used where convenient or desirable. Since most of the preferred adjuvants are freely soluble in lubricating oils, a wide range of homogeneous compositions can be prepared. Where desired concentrates can be prepared containing relatively large amounts, as for example 50%, of chloraralkyl esters of a thio acid. Such concentrates may be stored or transported in this form and diluted to the desired concentration before actual use. Complete solution is not always necessary and incorporation of the less soluble active agents in suspended form is suflicient to allow them to function in decreasing film strength in actual use.

There are a variety of procedures suitable for the preparation of the new adJ'uvants and in general any of the methods suitable for the prep- 1 Preparation 'of trichlor benzyl chloride Substantially 1500 parts by weight of dry toluene were charged into a chlorinator of suitable capacity. Substantially 15 parts by we'ight'o'f iron filings were added as catalyst'carrier for ring chlorination and chlorine introduced at about 20 C. until the. increase in weight corresponded to that calculated for trichlor toluene, The temperature was increased to 70 C. during the last part of the reaction and the flow of chlorine interrupted when the product analyzed 54.8% chlorine. The trichlor toluene was washed with caustic and filtered through aflbed or clay in order to remove the iron and chlorinated" at 160 C.- in the presence of ultra violet light until the gain in weight was that calculated for tially 0.33 molecular proportion). of Na2S.9HzO

trichlor benzyl chloride. Analysis of the product for chlorine at this point gave 61.8%.: f

EXAMPLE I TRICHLOR IBENZYL' TRITHIOCARBONATE perature of the reaction mixture was'he'ld at 25-" C. After the addition was complete, the temperature was raised to refluxing temperature for about four hours and the solvent removed as for example. by distillation undera Vacuum and the* residue washed with-water and dried. The prod- H u ct was a brown liquid which was readily soluble in mineral hydrocarbon oils;

EXAMPLE n TRIcHLoa BENZYL Burxz. Tmrrnocsasomim A mixture of 181.5 parts by weight (substantially 2.02 molecular proportions) of butyl mercaptan and substantially 1200 parts by weight of ethanol was added to 79 parts by weight of 95.5% o0 caustic soda (substantially 1.90 molecular pro portions), The mass was cooled to'f15 C. and 200 parts by weight (substantially 2.63 molecular proportions) of carbon disulfide addedth'eret'o molecular proportions) of trichlor benz'yl chlo The mass was 40 1 'tion) was d so ved *(substa'n bon dis'ulfide added. The temperature rose to 4 EXAMPLE .III

O-CH'LoR BENZYL BUTYL ITRITHIOCARVBONATE Into a reaction vessel of suitable capacity there was charged 49.5 parts byweight (substantially 0.55 molecular proportion) of butyl mercaptan and 20.7 parts by weight of 96.5% caustic soda (substantially 0.50 molecular proportion). The

mixture was diluted somewhat with ethyl alco-' hol, cooled to. 10 and 42 .0;- partsby v weight 1y 0.55. mple;cular proportion). of. car- 28 C. .fIhe mixture was then stirred for about 12 hours 'without heating and 725 parts by weight i(substantially' 0,45 molecular proportion) of orthqchlorbenzylchloride'added in ,a slow emixture was heated at 'or about three hours. The alcoholwas removed'by distillation and the .last traces stripped out-by heating mildly under a va'cuuiiif The residue was washed with water and dried leaving in good yield a reddish yellow liquid frely'soluble in mineral hydrocarbon lu-.

DrideCntoa emit) Tntrnrociieeomra i To as'olutio'n of 80 parts by weight (substan-' in substantially 400. parts by weight of methanol was added 27.8 partsby weight (substantial1y.

solution was stirred for seyeral' hour after which ring was continued ior about 1 2 hours after the addition or the or de and the'solyent the moved asjfloriexample by distillationgthe; last traces being stripped out byfmild .heat'ing under.

a vacuum. The residue w a .washed withwater and dried eavi g; in 'good yield a yellow liquid. i ire'ely soluble in" 'mineralhydrocarbon' oils.

G {The potassium salt of thimethyl carbonate 7 commonly known as Benders,salt g24' pa'rtsby weight or substantialIyDLIG'Zmolecular propor- M n tan ally. 209 Paris. by

" this-.lsql t on 36, a l l- 59 me e -e 1 eepin "l the'temperature of the reaction mixture.

ride was added in a slow stream during which.

the temperature of'the mass was kept at 30-40 C, The .mixture 'was then heated to refluxing temperature for four hours and the'solvent re 5 moved as tor exampleby distillation undera vacuum and the residue washed with water and a at 15-259 C; 58.4 partsby weight (substantially V 0.80 moleculart proportion) of diethyl-amine and uble in mineral hydrocarbon oils.

which caused the temperature to rise to about liqliid wdiq i i liilj el ld:F 28 C. 400'parts by weight (substantially 1.74 H I V H Emai -3st???be m:minimal sm substantially 80.5 parts byweight -(substane tially 0.35 molecular proportion) of trichlor lubricating,

0.37 molecularproportion); oi carbon. disulfide. keeping the: temperature below 309,0. The cold.

. rri was continued for s'ev'eralhdiirsland the mixturej allowed to standioigabouttlzghours after which'. it ;Was poured'iintfl an'exessoi water and the oil" extracteclwith ether?v orlotherflsuitable solvent, The solventlw'as removed and there siduedried benzyl chloride-was addedin 'a 'slowstieam 'to" u an ethanol solutionof the-diethyl amine salt of diethyl. dithiocajrbamic acid. prepared by reacting 404 parts byweight (su proportion) of carbon disulfide in substantially methanol.

bstantially'0.53 molecular 315 parts by weight of ethanol. The temperature was kept at -20 C. during the addition of the chloride. Without heating, the reaction mixture was stirred for about five hours and the solvent then removed by heating up to 40 C. under a good vacuum. The residue was washed with water, then dilute hydrochloric acid and finally with water again until neutral to litmus. The washing of the oil is facilitated by dilution with a suitable waterimmiscible solvent such as ether. After removal of solvent, drying and filtering through a bed of clay, a good yield of a brown viscous oil was obtained.

EXAMPLE VII DICHLOR DIETHYL PHENYL E'IHYL, ETHYL XANTHATE lar proportion) of the trichlor ethyl benzene so prepared was dissolved in substantially 238 parts by weight of acetone and the solution heated to refluxing temperature. Over a period of two hours'122.5 parts by weight of 91.5% potassium ethyl xanthate (substantially 0.7 molecular proportion) was added to the refluxing solution. Heating was continued for four hours, then the solvent removed, the residue washed with water,

dried and filtered through a bed of clay. An

oily product was obtained in excellent yield and was soluble in mineral hydrocarbon oils.

EXAMPLE VIII (It-(2,4 DICHLOR PHENYUETHYL TRITHIOCARBONATE Substantially 209.5 parts by weight (substantially 1.0 molecular proportion) of u-(2,4dlCh10I' phenyl) ethyl chloride was added in a slow stream to a solution of substantially 86 parts by weight (substantially 0.5 molecular proportion) of NazCSa in substantially 800 parts by weight of The mixture was stirred without heating for about an hour after the chloride had been added and then heated to refluxing temperature for about six hours after which the solvent was removed, preferably by distillation and the residue dissolved in a suitable water immiscible solvent, as for example benzene, and Washed with water. The solvent was again removed and the residue driedleaving in excellent yield a thin orange liquid soluble in hydrocarbon mineral lubricating oils.

CHLORINATION or DIETHYL BENZENE Per cent Chlorine Found Calculated Dichlorldal 3e. 9 35. o Trichlorida. 46. 1 44. 9 Tetrachlorid 53. 2 52. 2' Pentachloride 59. 0 57. 9

The fractions so obtained were reacted as hereinafter described.

EXAIWPLE IX DI(CHLOR ErHYL PHENYL ETHYL) TRI'I'HIOCAR- BONATE Substantially 84.2 parts by weight (substantially 0.5 molecular proportion) of diethyl benzene dichlorine was added slowly to a solution of sodium trithiocarbonate prepared by mixing 60 parts by weight of NazS.9H2O (substantially 0.25 molecular proportion) and 38 parts by weight (substantially 0.50 molecular proportion) of carbon disulfide in substantially 200 parts by weight of methanol. The temperature rose to 34 C. during the addition. Stirring was continued for four hours and the mass was then poured into water and the oil dissolved in ether or other suitable solvent and dried. A red oil was obtained after removal of the solvent which was soluble in mineral hydrocarbon lubricating oils. Analysis for sulfur and chlorine indicated that the product was essentially di(chlor ethyl phenyl ethyl) trithiocarbonate.

EXAMPLE X DI-DICHLOR ETHYL PHENYL ETHYL)TRITHIO- CARBONATE hours and the solvent removed as for example by distillation and the residue washed With water and dried. Substantially theoretical yield of a reddish oil was obtained which was freely soluble in mineral hydrocarbon lubricating oils. Analysis for sulfur and chlorine indicated the product was essentially di(dichlor ethyl phenyl ethyl) trithiocarbonate.

EXAMPLE XI DI(TRICHLOR ETHYL PI-IENYL ETHYL)TRITHIO- CARBONATE Substantially 54.5 parts by weight (substantially 0.2 molecular proportion) of diethyl benzene tetrachloride was added slowly to a solution of sodium trithiocarbonate prepared by mixing 24 parts by weight of Na2S.9H2O (substantially 0.1 molecular proportion) and 18.7 parts by weight (substantially 0.24 molecular proportion) of carbon disulfide in substantially 200 parts by Weight of methanol. Stirring was continued for four hours and the solvent removed as for example by distillation and the residue washed with water and dried. Substantially theoretical yield of a reddish oil was obtained which was moderately soluble in mineral hydrocarbon lubricating oils. Analysis for sulfur and chlorine indicated the product was essentially di(trichlorethyl phenyl ethyl) trithiocarbonate.

EXAMPLE XII DI(TETR.ACHLOR ETHYL PHENYL ErHYL) TRITHIO- CARBONATE Substantially 61.3 parts by weight (substantially 0.2 molecular proportion) of diethyl benzene pentachloride was added slowly to a solution of sodium trithiocarbonate prepared by mixagsssgtoe ing 24 parts by Weight of NaSZQH'zO (Substantially 0.1 molecular proportion) andl8i7 -parts b'y weight (substantially 024' molecular proportion) of carbon disulfide in substantially 200 parts by weight of methanol. Stirring'w'as"continud for four hours and the solvent removed as for example by distillation and the residue washed'wi th water and dried. Substantiallytheoretical yield solution of KOH with hydrogen sulfide and slowly adding 'benzoyl chloride to the cold solutlonacontaining an excess of KSl-I. The :free iaCidfWaS precipitated by the :additionof hydrochloric acid and then purified by dissolving in aqueous-"KOH until alkaline to phenolphthalein andthe solutionxevaporated. The salt was then dried at Substantially 40 parts by weight of the salt so prepared (substantially 0.227 molecular proportion) was suspended: in substantially 237 parts by was aded to a weight of alcohol and 471 parts by' weight (substantially 0.205 molecular proportion) .of trichlor benzyl chloride added in a slow stream. The reaction was slightly exothermic. After the addition of'the trichlor benzylchloride th /mixture was heated'to refluxing temperature for'about -three hours and the solvent removed. The residue was washed with water, preferablyaiterdissolving in a water-immiscible solvent, then dried and the solvent removed leaving the desired ester as a residue. The product wassolu-blein mineral hydrocarbon oils. Analysis for sulfur and proportion-flor d; or gpn'e' auueu and tne raction fluinng temperatu specifically a minor amonrit tif 'chlorarallyl ester high viscosity .hydrocarbon lubricating oil (Say-bolt Universal viscosity of 101 he conventional seconds :at stu f-1F.) rand sa'mples df tne blended lubricant subjectedflto ithMlmen Pin test described by Wolf and Mougey, Proc. A P. 1., .1932, pag s -118 -1f30fa'nd the""S. E. test: described in 'S.'-A.E.,'Jo1irr la1 39123 (11936).fihesetwote'sts 'are' commonly accepted itl'ieartaszstandardsto "determine the extreme pressure characteristics of a? lubricant.

"Imorderfforc 'n'iPgpropertieso has generallyfbee brine?toefiectivelyimprovethe consideifed necessarythat the 1ch'lt)i"ine"loie lifilged to an aupuat erafdi-cle. on the "other" hand;the resuitssetffoi thin the table below demon trate tnatu thecaseof-the newfadj vantsjfhlonn ;imk wto tu -aromatic markedly '"imp ovesfthir effectiveness." -ad- Arochlor,"whichis tne trade ma'jrke'd name of chlorinated diph enyhwa d'e v V "basefand compared with he. same'oil'basehontaming trich lor'fb enzyl 1311 l' tritli'iocarbonate in amount such'that thecmorinanusuirur "content chlorine without further purification g ave"9.2 *40 of the oil compositions were-identical.

' .Table I.v

*itidme giame-mts .1 z. lbstfailed a 7 Per cent 5' I Product Added jzmon g liifif gg n qgw :pm mgralo; 1 7 77-79-lbsJsecwloadl ingrate).:'

Dibenzyl trit-hiocarbonate 2.85 1 Arochlor 25s. :25 -3 I Di(trichlorbenz yl) tr1th1ocarbonate.- --7 39 3.3 965 40 Benzyl diethyldithiocarbamate--.. -7- 1"{8 0.10 :225 I :8 Trichlor'benzyl-diethyldithiocai'bain 7 1.3 {2. 2 7' 328 10 sulfur and. 33.8-% chlorine as-compared-to calapproximated that calculated for-ethyl triohlor benzene, Theproduct was distilled andtl'ie'tfraction boiling at QS-IM" C. was chlorinated at T 05in the absenceofiron-'until the" gain :in

Weight approximated tliat calculated for trichlor phenyl ethyl chloride.

Sodium ethyl xanthate was prepared by reactingbeloW' 45 0.1 substantially 76='parts'=by-'weight .0 molecular proportion) 'of carbon disulfide,

36.6-parts byweight- (substantia1ly:0.88- molecular proportion) of sodium hydro ride and substantially 316 parts by weight of ethyhalcohol. IS ubstantially 195.5 parts by Weiglrxt (0.8 molecular FroX-n th-e irei-egeinexamples it tvill 'be seen tliatthe chloi afa lkyliestrs of thisiirr'vention are hi'ghl-y emciefit extreme pressure ubri'cant bases -and :that the chloririg althougb it may be linked to the aryl group, markedly iinproves?tl re ffectiveness. .This is further brought out. bythe data set rorth'irf'rabie II, "Inaddit'iomtotests on the :Almen; machine thet increase. in yiscosity caused :by heatin the 0113 irr -thespresence of the tadditive,

-Were;a;lso determined. ;-The viscositydetermmat'ions were rnadeby heating -the-oil containingsthe R-additive for-m0jhours at 30fl ;;E'..-.-in open beakers. The visco ity act 1 the ;-;oil,-.- compositions .was .determinedat. 2102E..beforeandafter heat- :ingand the increase in viscosity-intpercent calculated.iromthe resultsobtained. Amarked .in-

wcrease inw-iscosity indicatesthat .viscoussgu-mmy constituents were formed *as the a result "of "oiridation alfdl'decompo'sfitioii 6f. the ioiliof theprdduct I addedorhoth.

mmerai hydrocarbonganic sulfur "compounds, it

iadlcle 0* a mineral oil The foregoing examples bring out the fact. that the presence of the chlorine actually seems to stabilize the oil compositions while at the same time improving the E. P. properties.

Other examples of the new lubricating oil compositions are set forth in Table III.

Table III S. A. E. (1000 R. 1%5'621 erecen ru ng re, Pwduct added in Oil 77-19 lbs/sec. loading rate) lbs. failed Di(chloro ethyl phenyl ethyl) trithiocarbonate 9.3 360 Di(dichlor ethyl phenyl ethyl) trithiocarbonate 7. 3 350 Di(trichlor ethyl phenyl ethyl) trithiocarbonate 6.4 310 Di(tetrachlor ethyl phenyl ethyl) trithiocarbonate 5. 9 360 Dichloro diethyl phenyl ethyl, ethyl xanthate 10. 0 370 O-ethyl S-trichlor benzyl monothlocarbonate 10. 0 313 Di(o-chlor benzyl) trithiocarbonate 7. 0 340 a-(2,4 dichlor phenyl) ethyl trithiocarbonate 10. O 364 Trichlor benzyl ester of benzothiolic acid 10.0 370 Trichlor phenyl ethyl, ethyl xanthate 10.0 358 The above data show the high efliciency of the new oil compositions. Obviously, other chloraralkyl esters of thio acids can be used where convenient or desirable. Particular mention may be made of tZ-(2,4: dichlor phenyl) ethyl, ethyl xanthate, di(methyl chlor benzyl) trithiocarbonate, dichlor phenyl ethyl diethyl dithiocarbamate, trichlor phenyl ethyl methyl xanthate, trichor phenyl ethyl amyl xanthate and the trichlor phenyl ethyl ester of benzothiolicacid.

Again, the foregoing examples are to be taken as illustrative of the invention and not limitative thereof. While the character of the invention has been described in considerable detail and numerous examples furnished of the preparation of the new additives and of the preparation and properties or" the new oil compositions, it will be obvious to one skilled in the art that numerous modifications and changes can be made. For example, the carrying agent for the extreme pressure agent can be varied widely. The inventon includes broadly the chloraralkyl esters of thio acids dissolved, dispersed or emulsified in any suitable carrying agent such as kerosene or other light petroleum hydrocarbons, benzene and other related hydrocarbons, alcohols, esters, ethers, fatty vegetable and animal oils as well as mineral hydrocarbon lubricating oils. This invention is limited solely by the claims attached hereto as part of the present specification.

What is claimed is:

1. A composition of matter comprising an admixture of a hydrocarbon lubricating oil base admixed with minor amounts sufiicient to impart E. P. properties to the lubricant of a chlor phenalkyl ester in which the ester forming group 10 consists of carbon, hydrogen and chlorine of' a thio acid the chlorine being attached'to the phenyl nucleus of the said phe nalkyl group.

2. A composition of matter comprising an admixture of a hydrocarbon lubricating oil base admixed with minor amounts sufficient to impart E. P. properties to the lubricant of a chlor phenalky1 ester in which the ester forming group consists of carbon, hydrogen and chlorine, of trithiocarbonic acid the chlorine being attached to the phenyl nucleus of the said phenalkyl group.

3. A composition of matter comprising an ad.-

mixture of a hydrocarbon lubricating oil base admixed with minor amounts suiiicient to impart E. P. properties to the lubricant of a chlor benzyl ester in which the ester forming, group consists of carbon, hydrogen and chlorineof a thio acid the chlorine being attached to the phenyl nucleus of the said benzyl group. A

4. A composition of matter comprising abase lubricating oiladmixed with minor amounts sur ficient to impart E. P. properties to the lubriicant of a chlor-ben'zyl ester in which the ester forming group consists of carbon,hy drcg n an'd chlorine, of a thiocarbonic acid the. chlorine being attached to the phenyl nucleus of thesaid benzyl group. n

5. A composition of matter comprising an admixture of a hydrocarbon lubricating oil base admixed with minor amounts sufiicient to im;- part E. P. properties to the lubricant of a chlor benzyl ester in which the ester forming group consists 01 carbon, hydrogen and chlorine of a thiocarbonic acid the chlorine being attached to the phenyl nucleus of the said benzyl group.

6. A composition of matter comprising an admixture of a hydrocarbon lubricating oil base admixed with minor amounts sufiicient to impart E. P. properties to the lubricant of a chlor benzyl ester in which the ester forming group consists of carbon, hydrogen and chlorine of a thiocarbamic acid the chlorine being attached to the phenyl nucleus of, the said benzyl group.

7. A composition of matter comprising an admixture of a hydrocarbon lubricating oil base admixed with minor amounts sufficient to impart E. P. properties to the lubricant of a chlor benzyl ester in which the ester forming group consists of carbon, hydrogen and chlorine of a trithiocarbonic acid the chlorine being attached to the phenyl nucleus of the said benzyl group.

8. A composition of matter comprising an admixture of a hydrocarbon lubricating oil base admixed with minor amounts sufiicient to impart E. P. properties to the lubricant of a compound of the type where R represents a radicle consisting of carbon, hydrogen and chlorine in the form of a chlor substituted aralkyl radicle having the chlorine attached to the nucleus of the aryl group and R represents any aliphatic or aromatic radicle and X represents an element of group VI of the periodic table of atomic number not more than 16. s

9. An extreme pressure lubricant comprising an hydrocarbon lubricating oil base and in admixture therewith a minor amount sufiicient to impart E. P. properties to the oil of a chloraralkyl ester of a thiocarbonic acid the chlorine being attached to the aryl nucleus of the said aralkyl Certificate of Correction Patent N 0. 2,438,599. March 30, 1948. EDWARD S. BLAKE It is hereby certified that errors appear in the printed specification of the above numbered patent requiring correction as follows: Column 2, line 8, in the formula, for (R-CHDH) read (R-CS.OH); column 6, line 9, for dichlorine read dichloride; column 9, lines 71 and 72, and column 10, lines 4 and 5, lines 12 and 13, lines 28 and 29, lines 36 and 37, lines 44 and 45, and lines 52 and 53, claims 1, 2, 3, 5, 6, 7, and 8 respectively, strike out the Words an admixture of; column 10, line 72, and column 11, lines 4, 11, 18, and 25, claims 9 to 13 inclusive, after ester insert in which the ester forming group consists of carbon, hydrogen and chlorine; and that the said Letters Patent should be read with these corrections therein that the same may conform to the record of the case in the Patent Ofiice.

Signed and sealed this 13th day of July, A. D. 1948.

THOMAS F. MURPHY,

Assistant Uommissioner of Patents. 

